descriptive mineralogy native...
TRANSCRIPT
Descriptive Mineralogy
Native Elements:Pure elements that occur
as minerals
Classification of the Minerals• Non-Silicates
– Native Elements– Halides– Sulfides– Oxides– Hydroxides– Carbonates– Sulfates– Phosphates
• Silicates– Orthosilicates– Sorosilicates– Cyclosilicates– Chain Silicates– Layer Silicates– Tektosilicates
Native Elements
Native Elements: Metals
• Fe, Co, Ni: Meteorites• Platinum Group: (Ru, Rh, Pd, Os, Ir, Pt):
Mafic Igneous Rocks• Coinage metals: Cu, Ag, Au
– Cu, Ag: Supergene Enrichments (SulfideOxidation)
– Au: Low Temperature Hydrothermal, Placer
Native Iron: Meteorites
Native Iron: MeteoritesWidmanstätten Pattern
Iron-Nickel Phase Diagram
Platinum Group MetalsRu, Rh, Pd, Os, Ir, Pt
• Strongly siderophile elements• Enriched in Fe meteorites• Found in layered mafic intrusions
– Bushvelt Complex (South Africa)– Stillwater Complex (Montana)– Skaergaard Complex (Greenland)
Bushvelt: Layered Gabbroic Intrusion
Bushvelt: Layered Gabbroic Intrusion
Skaergaard: Layered Gabbroic Intrusion
Skaergaard: Layered Gabbroic Intrusion
Skaergaard: Layered Gabbroic Intrusion
Native Elements: Cu, Ag, Au• Cu and Ag: Supergene Enrichment
– Oxidation of Cu, Ag sulfides inunsaturated zone
– Precipitation of metal, oxides andcarbonates at water table
• Ag and Au: hydrothermal– Native metals and tellurides
• Au: placer– oxidized hydrothermal
Supergene Copper
Hydrothermal Silver
Hydrothermal Gold
Hydrothermal Gold
Native Elements: non metals
• Carbon:– Graphite: Metamorphic Rocks– Diamond: Kimberlites
• Sulfur (+Se):– Salt Domes (Sulfate reduction),– Volcanos (H2S oxidation)
• Tellurium (Te) Tellurideoxidation
Native Elements: Carbon
• Graphite (Low Pressure)– Metamorphosed Organic-rich sediments
• Diamond (High Pressure >100km)– Kimberlites– Placers from kimberlites
Native Elements: Diamond
Native Elements: Diamond
Kimberley Mine 1875
Native Elements: Sulfur
• Fumaroles (Volcanic hydrothermal vents)– Oxidation of H2S
• Salt dome cap rocks– Sulfate reduction by petroleum
Fumarole Sulfur: Nysseros
Native Elements